Regenerated cellulose filaments containing a flame-retardant phosphonitrilate polymer and an organic phosphate salt to reduce filament to metal friction

ABSTRACT

Regenerated cellulose filaments and filamentary articles wherein the filaments have dispersed therein a mixture of (1) a substantially water-insoluble, liquid, organic phosphonitrilate polymer and (2) a substantially water-insoluble, organic phosphate salt, are disclosed herein.

Feller 51 May 15, 1973 [54] REGENERATED CELLULOSE [56] References Cited FILAMENTS CONTAINING A FLAME- RETARDANT PHOSPHONITRILATE UNTED STATES PATENTS ?OLYMER AND AN ORGANIC 3,058,941 10/1962 Birum ..l06/l77 ux H PHA E SALT T REDU 3,238,248 3/1966 Rawhut ...260/429 9 X 3,266,918 8/1966 Schappel et al. ..l06/l 77 X FKLAMENT To METAL FRICTION 3,505,087 4/1970 Godfrey [75] Inventor: Jay M. Feller, Wilmington, Del. 3,532,526 10/1970 Godfrey-m 3,455,713 7/1969 Godfrey .264/194 X [73] Assignee: FMC Corporation, Philadelphia, Pa. [22] Filed: Mar. 25, 1971 Primary ExaminerDonald E. Watkins [21] Appl. No: 128,189 Attorney-Thomas R. QMalley [57] ABSTRACT [52] Cl "57/140 106/177 260/4299 Regenerated cellulose filaments and filamentary arti- 106/164, 16/165 cles wherein the filaments have dispersed therein a [51] Int. Cl. ..C09k 3/28, DOlf 3/12 mixture f 1 a Substantially watepinsoluble, liquid,

Fleld of Search R, C, organic pho phonin-ilate polymer and a ubstan- 57/140 BY; 106/164, 177; 260/4299; tially water-insoluble, organic phosphate salt, are dis- 264/194 closed herein.

7 Claims, No Drawings REGENERATIEID CELLULOSE FILAMENTS CONTAINING A FLAME-RETARDANT PHOSPHONITRILATE POLYMER AND AN ORGANIC PHOSPHATE SALT TO REDUCE FILAMENT TO METAL FRICTION- Regenerated cellulose filaments containing flameretardant amounts of substantially water-insoluble, liquid organic phosphonitrilate polymer dispersed therein are known in the art. Forexample, U.S. Pat. Nos. 3,455,713, 3,505,087 and 3,532,526 disclose these flame-retardant filaments.

Textile mills have experienced difficulties in the high I speed spinning (manufacturing) of yarns prepared from these flame-retardant filaments, particularly with medium to fine count staple fiber yarnsranging, for example, from 20/1 to 80/1. Traveler wear. on ring winders and ends down of the spun fiber have been excessive and the yarns have been hairy from the picking, carding, drafting and roving operations prior to yarn spinning. As the spindle speed increases to about 8000 R.P.M. and higher, travelers burn andpop-off at a frequency far above normal or toleration.

It is an object of this invention to provide regenerated cellulose filaments containing. water-insoluble liquid phosphonitrilate polymer which, when in the form of yarn and spun at high speeds, demonstrate reduced filament breakage and improved traveler wear in winding without degrading the flame-retardant.properties of the yarn.

It is another object of this invention to provide a method of preparing regenerated cellulose filaments containing both water-insoluble liquid phosphonitrilate polymer and a water-insoluble, oil-insoluble, organic phosphate salt dispersed therein.

These and other objects are accomplished in accordance with this invention which comprises regenerated cellulose filaments and filamentary articles, the filaments having dispersed therein (1) a substantially water-insoluble, liquid phosphonitrilate polymer in an amount sufficient to provide improved flameretardancy for the filaments, and (2) a water-insoluble, oil-soluble, organic phosphate salt in an amount sufficient to decrease filament to metal friction.

The method of this invention comprises mixing viscose, a flame-retardant amount of a substantially water-insoluble, liquid phosphonitrilate polymer and a wear-retardant amount of a substantially waterinsoluble, oil-soluble, organic phosphate salt, shaping the mixture into filaments, and coagulating and regenerating the filaments.

The substantially water-insoluble, liquid, organic, phosphonitrilate polymer is preferably that disclosed in U.S. Pat. No. 3,455,713 to L. E. A. Godfrey, issued July 15, 1969. However, liquid phosphonitrilates having the following general formula wherein X and Y represent the same or different substituents including OR groups wherein R is aliphatic, cycloaliphatic, aromatic or heterocyclic, said aliphatic radical being straight or branch chained and having 1 to 12 carbon atoms, preferably R is an alkyl or alkenyl radical having from 2 to 6 carbon atoms, said cycloaliphatic radicals have 4 to 6 carbon atoms and said aromatic radicals have 6 to 10 carbon atoms; R may also have substituent groups including halogens, ether or amino groups. X and Y can also be SR wherein R is as previously described. Some of the X and Y substituents can remain halogens from the phosphonitrilic halide polymer from which the ester was derived. Usually, the halogen will be chlorine. X and Y substituents also include NR,R wherein R is hydrogen and R is a lower aliphatic group or R and R are lower aliphatic, cycloaliphatic or aromatic groups as described for R above or together R R and N form a 5 or 6 membered nitrogen containing heterocyclic group. n in the above general formula is at least 3. The flame-retardant material must be a pumpable fluid in accordance with this invention, thus 11 on. an average must be low enough to meet this requirement.

The flame-retardant is added to the viscose, preferably by injection under pressure into the viscose line of the spinning machine such that the flame-retardant is thoroughly mixed in the viscose when extruded from the spinneret. The flame-retardant amount, as referred to herein, is generally an amount sufficient to provide from about 1 to about 30 percent thereof in the conditioned filament. Preferably, the filament will contain from 5 to 25 percent by weight of the flame-retardant. The rate of injection of flame-retardant into the viscose is controlled to obtain the desired product.

The water-insoluble organic phosphate salt includes salts of divalent metals, for example, calcium, barium, strontium, magnesium, zinc, mercury, cadmium, tin, etc. and salts of the ethanolamines, for example, monodiand triethanolamines. Preferably, the phosphate metal salts include the zinc or barium salts of dihydrocarbyl substituted dithiophosphates disclosed in U.S. Pat. No. 2,540,084. The hydrocarbyl radical is most preferably an alkylated cyclohexyl radical wherein the alkyl groups have from 1 to 6 carbon atoms. Other water-insoluble, organic phosphate salts, which are generally known to be useful as anti-wear and extreme pressure agents in mineral oil and synthetic motor oil lubricant compositions, and which are useful for this invention include, for example, the dialkyl phenoxyalkyl dithiophosphate metal salts, the dialkylphenyl dithiophosphate metal salts, mixed dialkyl dithiophosphate metal salt wherein the alkyl groups range from 1 to 18 carbon atoms. The metal salts are usually supplied as concentrates dissolved in mineral oil or other oleaginous liquids and these have been compatible with the compositions of this invention. The amine salts include, for example, mono-, dior triethanol amine salts of dialkylphosphate, bis-mono-, dior triethanol amine salts of monoalkylphosphate, methylaminoethano] salts of dialkyl phosphate, bis-methylamino-ethanol salts of alkylphosphate, dimethylaminoethanol salts of dialkyl phosphate, bis-dimethylaminoethanol salts of alkylphosphate, methylaminodiethanol salts of dialkylphosphate, and bis-methyl-aminoethanol salts of alkylphosphate wherein the alkyl groups range from 6 to 16 carbon atoms. It should be understood that the alkyl The phosphate salts are incorporated in the filament in a wear-retardant amount generally ranging from about 0.25 to about percent based on the weight of the phosphonitrilate flame-retardant. Preferably, the phosphate salt is incorporated in an amount ranging from about 0.5 to about 6 percent.

To prepare the regenerated cellulose filaments of this invention, the phosphonitrilate flame-retardant and the phosphate salt are mixed with filament-forming viscose, the mixture is extruded in the form of filaments and the filaments are coagulated and regenerated by known means. Preferably, the phosphate salt is mixed with the phosphonitrilate flame-retardant in the prescribed amount and the mixture injected under pressure into the viscose line in a spinning apparatus just prior to extrusion into a coagulating and regenerating bath. Other conventional additives used in the manufacture of viscose rayon yarn may also be mixed with the viscose. The spun (extruded) filaments are brought together in the form of a yarn after extrusion and the yarn is processed in a known manner.

If desired, suitable organic solvent solutions of the flame-retardant and phosphate salt of this invention can be used for mixture with the viscose, although this is not a preferred technique.

In the manufacture of staple filament yarn, the continuous filament yarn is cut into short lengths and a finish may be applied. These staple fibers are sold and shipped to textile mills which manufacture the staple fibers into spun staple yarns on very high speed machinery.

The following example is set forth to demonstrate this invention.

EXAMPLE I A mixture of water-insoluble, liquid di-n propyl phosphonitrilate polymers and 1 percent of a waterinsoluble, 50 percent mineral oil concentrate of zinc dialkyl dithiophosphate (Lubrizol-677), based on the weight of the phosphonitrilate, was mixed with filament-forming viscose by pumping it into the viscose line of a spinning apparatus prior to spinning. The mixture was pumped into the viscose at a rate sufficient to provide a conditioned filament yarn having dispersed therein about 25 percent flame-retardant. The viscose comprised 8.2 percent cellulose, 6.2 percent sodium hydroxide and 34.0 percent carbon disulfide, based on the weight of the cellulose. The viscose mixture was extruded in the form of a plurality of filaments into an aqueous coagulating and regenerating bath comprising 9.0 percent sulfuric acid, 2.0 percent zinc sulfate and 15.0% sodium sulfate at a bath temperature of 55C. The filaments, after stretching, had a denier of 1.5 and were conventionally processed including washing, desulfurizing, bleaching, etc. The continuous filament yarn was cut into staple fiber, and a finish comprising a glycerol ester of a coconut soap with an excess of fatty acid was applied to a blanket of the never-dried staple in an amount of about 0.2 percent based on the weight of the fiber. Some of the continuous filament yarn was separately dried and tested for inflammability as described in U.S. Pat. No. 3,455,713. The yarn was rated as excellent in flame-retardant properties.

The staple fiber was dried and baled. Thereafter, it was then taken from the bale, and conventionally processed by picking, carding, drawing and roving. The roving was spun into a fine count yarn (/1) and packaged at a spindle speed of 12,000 R.P.M. The traveler employed on the winder was a Carter Imperial (Slotted) Traveler with Miracle (Nickel alloy) finish. The traveler did not need to be replaced and after about 20 hours the run was completed. Ends down (40) and hairy yarn problems were improved to a significant degree. In comparison, in similar runs wherein the flameretardant filaments do not contain a phosphate salt to inhibit wear, the traveler must be replaced after about 0.5-4 hours and ends down are unexceptably high (200). Furthermore, in high speed spinning runs wherein the phosphate salt is omitted and the traveler is not slotted, the traveler must be replaced every few (1-4) hours indicating that this type of traveler is essential for high speed winding of this product.

A preferred staple fiber finish is the glycerol ester employed in the example, however, known finishes for cellulose fibers can also be employed. For example, ethylene oxide modified higher fatty acids, ethylene oxide modified fatty alcohols, sorbitan esters of fatty acids and ethylene oxide modified sorbitan esters of fatty acids, sulfated fatty acid esters, fatty acid salts, fatty acid ester salts, mineral oils, vegetable oils, quaternary ammonium compounds, etc., and mixtures thereof are useful for this purpose.

EXAMPLE 11 Example I was repeated except that a mixture of the di-n-propylphosphonitrilate polymers and 5 percent, based on the weight of the phosphonitrilate polymer, of monoethanolamine alkyl phosphate wherein the alkyl group has from 6 to 16 carbon atoms (Atlas [1.424) was injected into the viscose. The flame-retardancy of the fiber was excellent and traveler wear, ends down (58 ends down) and hairy yarn problems were greatly reduced.

Various changes and modifications may be made in practicing the invention without departing from the spirit and scope thereof and, therefore, the invention is not to be limited except as defined in the appended claims.

I claim:

1. Regenerated cellulose filaments and filamentary articles, said filaments having dispersed therein (1) a substantially water-insoluble, liquid phosphonitrilate polymer in an amount sufficient to provide improved flame-retardancy for the filaments, and (2) a substantially water-insoluble, oil-soluble, organic phosphate salt in an amount sufficient to decrease filament to metal friction.

2. The regenerated cellulose filaments and filamentary articles of claim 1 wherein said articles are spun staple yarns.

3. The regenerated cellulose filaments of claim 1 wherein the phosphonitrilate polymer is a di-R phosphonitrilate and R is selected from alkyl and alkenyl groups containing from 2 to 6 carbon atoms, and said phosphonitrilate polymer is present in an amount ranging from about 5 to 25 percent based on the weight of the filaments.

4. The regenerated cellulose filaments of claim 1 wherein the phosphate salt is a divalent metal salt of a di-hydrocarbyl dithiophosphate or an ethanolamine salt of an alkyl-phosphate and the phosphate salt is present in an amount ranging from about 0.5 to about 6 percent based on the weight of the phosphonitrilate polymer.

of an alkyl-phosphate which is present in an amount ranging from about 0.5 to about 6 percent based on the weight of the phosphonitrilate polymer.

7. The regenerated cellulose spun staple yarns of claim 2 having a finish for cellulose fibers applied to the surface thereof. 

2. The regenerated cellulose filaments and filamentary articles of claim 1 wherein said articles are spun staple yarns.
 3. The regenerated cellulose filaments of claim 1 wherein the phosphonitrilate polymer is a di-R phosphonitrilate and R is selected from alkyl and alkenyl groups containing from 2 to 6 carbon atoms, and said phosphonitrilate polymer is present in an amount ranging from about 5 to 25 percent based on the weight of the filaments.
 4. The regenerated cellulose filaments of claim 1 wherein the phosphate salt is a divalent metal salt of a di-hydrocarbyl dithiophosphate or an ethanolamine salt of an alkyl-phosphate and the phosphate salt is present in an amount ranging from about 0.5 to about 6 percent based on the weight of the phosphonitrilate polymer.
 5. The regenerated cellulose filaments of claim 3 wherein the phosphate salt is a zinc or barium salt of a dialkyl dithiophosphate which is present in an amount ranging from about 0.5 to about 6 percent based on the weight of the phosphonitrilate polymer.
 6. The regenerated cellulose filaments of claim 3 wherein the phosphate salt is a monoethanolamine salt of an alkyl-phosphate which is present in an amount ranging from about 0.5 to about 6 percent based on the weight of the phosphonitrilate polymer.
 7. The regenerated cellulose spun staple yarns of claim 2 having a finish for cellulose fibers applied to the surface thereof. 